Quantitative intravascular biological fluorescence-ultrasound imaging of coronary and peripheral arteries in vivo.

source: © 2016 European Heart Journal

(i) to evaluate a novel hybrid near-infrared fluorescence—intravascular ultrasound (NIRF-IVUS) system in coronary and peripheral swine arteries in vivo;  (ii) to assess simultaneous quantitative biological and morphological aspects of arterial disease.
Methods and results
Two 9F/15MHz peripheral and 4.5F/40MHz coronary near-infrared fluorescence (NIRF)-IVUS catheters were engineered to enable accurate co-registrtation of biological and morphological readings simultaneously in vivo. A correction algorithm utilizing IVUS information was developed to account for the distance-related fluorescence attenuation due to through-blood imaging. Corrected NIRF (cNIRF)-IVUS was applied for in vivo imaging of angioplasty-induced vascular injury in swine peripheral arteries and experimental fibrin deposition on coronary artery stents, and of atheroma in a rabbit aorta, revealing feasibility to intravascularly assay plaque structure and inflammation. The addition of ICG-enhanced NIRF assessment improved the detection of angioplasty-induced endothelial damage compared to standalone IVUS. In addition, NIRF detection of coronary stent fibrin by in vivo cNIRF-IVUS imaging illuminated stent pathobiology that was concealed on standalone IVUS. Fluorescence reflectance imaging and microscopy of resected tissues corroborated the in vivo findings.
Integrated cNIRF-IVUS enables simultaneous co-registered through-blood imaging of disease related morphological and biological alterations in coronary and peripheral arteries in vivo. Clinical translation of cNIRF-IVUS may significantly enhance knowledge of arterial pathobiology, leading to improvements in clinical diagnosis and prognosis, and helps to guide the development of new therapeutic approaches for arterial diseases.[Read more…]

Intravascular cNIRF-IVUS image

Intravascular cNIRF-IVUS imaging with the 4.5F/40MHz catheter reveals the value of IVUS-based distance correction of the NIRF signal in blood. In vivo cNIRF-IVUS imaging of a swine carotid artery was performed following local injection of an NIR fluorophore into the artery wall. Panels (A), (B) and (C) illustrate the in vivo cNIRF image, the corresponding longitudinal IVUS image, and the FRI image of the resected artery, respectively. (D) A 3D representation of the lumen and arterial wall NIR fluorescence signal rendered based on the in vivo cNIRF-IVUS image stack. Insets (C1–C3) show representative examples of the cross-sectional cNIRF-IVUS images corresponding to pullback positions C1, C2, and C3 in (B), (C), and (D). The cNIRF signal in C1, C2, and C3 is fused onto the interior of the IVUS catheter and also replicated at the exterior (outlined with red dotted lines) of the IVUS image. (E) Serial imaging of the same vessel region demonstrates that the raw NIRF signal (top row) is affected by variable intraluminal catheter position that changes the distance between the NIR fluorescence source and imaging catheter detector, leading to fluctuations in the measured NIRF signal. Note that applying the NIRF distance correction (bottom row) substantially improved the reproducibility of the NIRF image and reduced the variability due to changes in catheter position. (F) Quantitative assessment of the improvement of the reproducibility by NIRF distance correction: black dots correspond to the maximum NIRF signal vs. pullback position, and the blue line indicates the average distribution function. Distance correction improved the correspondence between NIRF signals from all three pullbacks from R2 = 0.89 to R2 = 0.96.

Dmitry Bozhko, Eric A Osborn, Amir Rosenthal, Johan W Verjans, Tetsuya Hara, Stephan Kellnberger, Georg Wissmeyer, Saak V Ovsepian, Jason R McCar. European Heart Journal – Cardiovascular Imaging, Volume 18, Issue 11, 1 November 2017, Pages 1253–1261.